Apparatus for erasing thermoplastic phonograph records



Jan. 22, 1952 v A. KEGAN 2,583,297

APPARATUS FOR ERASING THERMOPLASTIC PHONOGRAPH RECORDS Filed July 51, 1948 y 4 5 sheets-sheet 1 IN VEN TOR.

BYZber f Kegel/z,

.Ian.`22, 1952 A. l. KEGAN l2,583,297

APPARATUS FOR ERASING THERMOPLASTIC PHONOGRAPH RECORDS Filed July 31, 1948 5 Sheets-Sheet 2 INVENTOR.

93 Alberi l Rega/L 1 WMM@ 5 ffy@ 5 Sheets-Sheet 3 INVENToR. Alber/5 fegczfz, BY Kuri/vm M I APPARATUS FOR ERASING THERMOPLASTIC PHONOGRAPH RECORDS j@ la Jan. 22, 1952 Filed July 51, 1948 Jan. 22, 1952 A. l. KEGAN 2,583,297

APPARATUS FOR .ERASING THERMOPLASTIC RHONOGRAPH RECORDS Filed July 51, 1948 5 sheets-sheet 4 INVENTOR.

Blberl Kegel/,m

ff/6 WWW@ Jan. 22, 1952 A. l. KEGAN APPARATUS FOR ERASING THERMOPLASTIC PHONOGRAPH RECORDS Filed July 31, 1948 5 Sheetsv-.Sheet 5 INVENTOR.

Patented Jan. 22, 1952 ARBARATUsLEQRtERAsmQTHERMO- rLAsgrxcrnoNoGnarnnnoonns.;

Albert Ii Keganhicago, Illirassignorgshyfmesne; assiaxmientsik tor Thomas.:` Ar; Edison; Ineorpof 1 ratedmwestsQranggaN. J., a corporation of New Jemen.

The presentJinvention relates` to. resurfacing-l thermoplastic articles.` and` to novelfapparatuseforf that'purpose. Theinvention'fis.especiallygadaptedil to` reclaiming used. phonographic.; disk records: made of thermoplastic materia1;.'hyf` erasing..the.y sound tracks` therefrom.y

This I. accomplish thermally,y by.; heating; att. least the surface-.ofthe :thermoplastic article: to., avitemperature suicient to substantiallylobliter.- atesurface irregularities. Since thin thermos; plastic`| articles; such as.t record; disksj made ofi plastic rigid sheets of polyvinyl:chloridesacetatel resins and extensively used inolicedictatimg.'mae chines, become toc fiaccidto maintain their-.shapes at such temperatures, andsticktc `almostx,anys.- thing when their limpnessrresultsin.contact:l; nd it convenienttc .maintainatheir sl1'ape\..dmt-4 ing the heat treatment byrcentrifuging them". Articles such as uphonographic recordgdisksmcrs.. mally Warp so much on cooling Vasfto bevvert-hless: and ugly.` Iv have discovered 'that .such .warpingfv may be preventedY by centrifugingthe disks: during cooling and until they take afipermanentisea;

Phonographic apparatus utilizingzthernioplase.

tic records have come into. Wideespread usefzinfl- 25 recent years, particularly` in the: eldsaofffhomes recording and office machine'dictation. Oneifofff: the principal. reasons for thispopularity isz-that; such records givcreccrdngsof higln fidelity; and.: are nonfrangible, light in Weight; paper: thin, and;v convenient to le wherethe-original1record;:.isi worth preserving. Prior tothefpresent inventiom. however, it has been` impossible. torre-user thermoa. plastic records.

In the eld of machinefdictation, this iresulteds in high operating costs, since vthe .records are usually discarded after being:transcribed;v Thisf has been a serious .obstacleto. the. adoption-1ct: disk-type dictating machines-,f for the competi-f... tive cylinder type dictating machines employyvax; record cylinders which canbe shavedandre-used; 75 times or more.

Prior to my invention, ithasfnotfbeenieasille to obliterate surfaceirregularities suchcaszsounds track from thin thermoplastic sheetsrandctogiyer ,g5-f

blankriupon Whicha new. sound tracksmawbc-.r-

larities from a surface of a thermoplastic -articlc,=..

graph disk recording made on thermoplastic :mae-1 teria'l;` so..that'said..disk. may.; be. re-used.; as a recorded..

A Another'fimportant object isto .provide conviene` ient apparatus forielectuatingzthe .f oregoinggobw.- jects:`

Yet another-obi ect is to `provide. apparatus.. fors' erasing.; phonographicf.v disk records, which .i apr. paratus is suitable for office use by.- an unskilled.

operator:-

Still another:- object is ito.provdef.automaticapff v paratusft'or the :purposes stated..

Another object .of. myt invention is. to prox/ide.;

apparatus .which Aissimultaneously.capable;ofreprocessingca; plurality. of usedrecords, and their infa-,shortfinterval-of time.

In order that imyinvention. maybe: more fully;

disclosed,1 reference ishad tothe accompanying drawings which` exemplify: apparatus. for.' carry-t ingfoutmy. novel method andrwhich emhodythe foregoing ,and .such other.. principles,. .advantages` orcfcapabiliti'es asrmay be pointedont aspthispde# scription. proceeds; or as are .mherentin'.1;l'ie.':i: r.es.. ent invention. For purposes of clarity inteach.-V

ing snovel .f method, the.- following. A description ofirsnitable.: apparatuss. made.; explicit.. andzthe@ accompanying drawings are detailed, but itissdisftinctly': to :.be understood .that my novel .methods mechanical4 means. disclosed..

In. the..drawings:

Figurelis..aafront.'elevationiview.aofiapparatus. for?performing;` my;l novel. processes,` especially.;

upon phonographicgdisk records.;

Figuret 2.is.A a sideaelevational vieu/...of ther-art` paratusbf Figure 1;

I Figure is a;fragmentaryjside-elevational' View; ofrthaespindle.; .themotor f andgiitsfbase in vreOr-d.

loadinaand-unloadins D OsitOn;

FigureApisra fragmentary plan elevatonaLview-f oftztherapparatusycf Figure 1,;

Figure.xzisial fragmentary detail; pl an .elevaf` tional. view of' the base andI track alongwhichathefheatingfjchamber moves;

Figure. 6 .is i al fragmentary i front elevationall view italien in sections on` theline` c fof,- Figure 6525;; .showing-the sprins loaded sea-r.whichfexerts-faa restoring force upon the heating chamber as the latter is moved from the position of Figure l;

Figure 7 is a front elevational view of the apparatus of Figure 1 in record heating position;

Figure 8 is a front elevational View of the ap paratus in the operative position of Figure 7, taken iirvertical central section and with por tions of the records broken away to better disclose the construction of the heating chamber;

Figure 9 is a front elevational View of a washer which is used to space the recordsV on the spindle;

Figure 10 is a detail fragmentaryfront elevational view in cross section, .Showing thel catch mechanism for retaining the heating chamber in record heating position; I

-. Figure 11 is a view similar to Figure 9, but

showing the catch mechanism disengaged puo;

motor 2U pivots on the pins 24, 24 journaled by a pair of trunnions 25, 25 projecting from the pedestal 26. The pedestal 26 in turn is mounted upon the frame 21 of the apparatus. By means of this arrangement and the stop 23d forming part of the base 23, the motor 20 may be tilted through 90 (Figure 3) to facilitate placing records 22 upon the spindle 2|. As best shown in Figure 8, the cross section of the spindle 2| .preferably conforms to the shape of the center opening 22D of the record 22.

In'placing the records 22 upon the spindle 2|, therstrecord is butted against the collar 28 secured permanently to the spindle 2|, following which washers 29 (Figure 9) and records 22 are placed alternately upon the spindle 2| until the n desired number of records 22 has been thus mounted. For purposes of securing a rigid as- Figure 12 is a schematic electrical circuit'V d1agram of the apparatus shown in the preceding figures;

Figure 13 is a fragmentary detail view in cross section, illustrating a modied form of the spin-v dle of the motor;

vFigure 14 is a front elevational view of another;

embodiment of apparatus for performing my novel processes, with parts thereof broken away to show a portion ofthe apparatus comprising anautomatic program .control system;

Figure 15 is a plan elevational View taken on :.1

tional view taken on the line |6|6 of Figure 14 13..

i .Figures 2O through 2,3 inclusive, are front ele.- vational views of the cams driven by the timer element.

Like reference characters designates likel parts.- in the drawings and in the description which follows. As indicated above, the method may be realized by heating a used disk record until plastic ow occursv and sensibly obliterates the soundv track.. Thereafter, the hot record preferably is spun in a cooling atmosphere until it has set. In

practice, advantages are obtained by spinning the record throughout both the heating and the cooling portions of the cycle. In addition, I prefer to grasp the record only upon the unrecorded portion adjacent its center hole, so thatthe sur.- face being erased does not come in contact with any object throughout the reprocessing cycle.

Referring now more particularly to the drawings, Figures 1 and 2 taken together show apparatus which performs the foregoing operations.. Said apparatus comprises three principal cooperating subassemblies, namely (a) mechanism for spinning the records, (b) apparatus for heating the records, and (c) means for controlling these subassemblies and their relation to each other.v

The spinning mechanism includes the electrical motor which turns spindle 2|, shown carrying several records 22 having sound tracks 22a there"- on 'which are to be erased. 1 The base 223 of the'.

sembly upon the spindle 2|, the center opening I, 29a of the washers 29 is made to conform to the center opening 22h of the record 22 (see Figu're 8). To clamp the records 22 firmly in place on the spindle 2|, a spacer 30 of appropriate length is first placed on the spindle 2|, following which the center tapped knob 3| is screwed onto the threaded portion 32 of the spindle 2|, thereby causing the Washers 29 to grasp the records 22 on the center unrecorded portions thereof. Thus the records 22 are spun by frictional engagement with the Washers 29, thereby minimizing any tendency toward slippage between the spindle 2| and the records 22 and preventing consequent distortion of the center holes 221) of the records 22. Because the records are secured in place by means of frictional engagement with the washers 29, it is not essential that the cross section of the spindle 2| correspond exactly with that of the record 22. Thus for example, a spindie 2|' (Figure 13) having a circular cross section may be used to advantage where the record 22' has a spline-shaped central opening 22h.

As best shown in Figures 1 and 2, the heating chamber comprises a U-shaped connecting member 4| and a pair of side members 3l and 38, each of which is provided with a slot (39 and 4D respectively). The slots 39 and 40 are dimensioned to provide clearance for the spindle 2| and the spacer when the chamber 36 is moved to enclose the records 22. As best shown in Figures 2 and 8, the interior Wall surfaces of the heating chamber 36- are lined with insulation 65 to which electrical heating elements 42 are secured, the elements 42 preferably being arranged in a grid pattern which gives an even distribution ofheat throughout the chamber 36.

As is clearly shown in Figures 2 and 5, the mechanism for effecting an operative relationship between the heater 36 and the records 22 includes a channel 33 secured to the frame 2 and provided with a pair of retaining rails 34 and 35. Thus a track is provided along which the heater 36 is rollable.

The heatingv chamber 36 is secured along its bottom portion to the carriage 43, which is pro vided with a plurality of rollers 44 adapted to rit withinand be retained by the rails 34 and 36. The heating chamber 36 is provided with a handle 45 for pulling said chamber along the channel 33.

As best shown in Figure 8, a rack 3E is securedto the under portion of the carriage 43 and meshes with a pinion gear 41 projecting upwardly through the slot 41a in the channel 33. The pinion gear 41 is spring-loaded (Figure 6) by means of a torsional spring 66 coiled upon the shaft 61, said .shaft 61 being journaled by the.

studsz' and Bil. As the `heating chamberl -is moved to enclose the records 22 upon `ihz'ispin'dle 2 I` 'and reaches the endet .the channel 3`3,a`catch 43 (Figure l0) engages the notch 49 in the carriage 43 and prevents the restoring force of the spring i-roin returning. the -heating chamber 36 until said c'atchis released (Figure V111).. :Said catch 48 extends througnan opening 50 in the track 33' and is spring-loadedbyV thehelical spring 5l (Figure l0). To prevent anyJposs'ibility-of the carriage i3 overrunning the'end of. the chalinel 33, I provide an end'st'op 19. Similarly, the stop 1i denes the rest posi-tion vortheheating chamber 3E when the apparatus-isy not in use.

Advantageously, my' 'novel apparatus .may be adapted toethei emioi' fully automatic. opera#v tien, thereby securing uniform results even` Yin the hands et unskilledfoperators'. @nenovelV electromechanical system whereby semi-'automatic operation'is achieved, is shown lin simpliiied rform in Figure l2, taken in conjunction-with Figure 5. In this system, the carriage 43 engages a pairof spring-loaded push-pull switches 52 and53 as it moves along the channel 33. The switch 52T is in circuit 54 whichjwhen closed, connects the motor '2li to the electric power line'55. A second circuit '5t containingY the switch`53 is in parallel with circuit '5e'. lUpon closing theswitch 53, therefore, the heating elements 2 .of the 'heating chamber 3S are energized. Consequently, as the heating chamber 3E is moved along the channel 33 toward the spindle 2l, the motor 2'0- starts to spin the records 22V and the heating elements 42 warm up. Upon reaching theend of theA channel 33, the carriage y43 engages the catchwc'lll,l and simultaneously closes the vspring'-'loaded'pushepull switch 51, which forms a partfof circuit- 581, which is also in parallel with circuits 54 yand '56.' Glosing said switch 51 energize's` an electrical timer mechanism 5S. A shaft iil'iand` a carne! (best .51.

shown in Figures l0 andl ll) 'forma part of? the timer mechanism 59 and contact the trip lever 62 of the catch lill. After a pre-determined length of time, which is regulated by adjustment ofthe pointer E53 along the time scale Ell,` the carn- Bly rotates through 360 and in so doing disengages the catch t from the notch 49, therebyper# mittingthe spring- 'i "tof return the heater" `3lifto` its inoperative position. Afterlthe' cam BI returns to the null position, theA spring -Eil returns the catch 43 to the up position.

The preferred manner in which theV above described apparatus is used-to carry out my novel processes, is as follows: lThe operator iirst'tilts the motor Eil into the position'v'` shown inl'igure 3, thereby presenting the spn'dlel2l in a position which facilitates loading` the records 22 thereon. Aiter placing the recordsl 22 and the spacers'29 on the spindle 2l and securing thelninV place in the manner already described, they operator returns the motor to the position shown in Figure 2, grasps the handle 4v 5 and pulls the heater 33 along the channel 33 until thefcatchfrand notch K13 lock the heater 3&5` over the records. By wiring the motor 2li. to turn'in a counterclockwse direction (Figure l) and threading the 'portion 32 and the knob 3| with ay righthand thread, 'rota tion of the records tends, if anything', totighten the knob 3l uponthespacer 30, "Thus the records 22 are held firmly` in place Whilespinning'.

rIfhe apparatus now spins and'heatsytherecords for the predetermined intervalof time, which is sufficient to raise the 'surface temperature ofv the records high enough to obliterate thetsoundtrack.

" 'Auvantageous1y; the' centrifugal forces' acting upon the sunfacesioffthefspinning .recordsA 22 auge; ment the surface tension forces; andhasten flow of the surface and c'r'u'isequenterasure of the soundV track. Even more important, the eene4 trii'ugal force maintains the. recordsA in a planar conguration.

After the requisitelength ofk time required for obliteration of the sound tracks'has elapsed, the timer mechanism 5S causes the. cam 6l to release the catch 48, thereby permitting thesspring-.elcaded pinion gear 41 to rotate clockwise (Figure 8) yand move vthe heating chamber 36; to the right until the carriage. comesfto rest `against .the stop 11|. As the carriage '43 'returns' tol the null position, the switches 52, 53,1a-nd 51 op'enthe motor (circuit 5d, the` heating element circuit 56 and thetime circuit 58, respectively, therebyfturni-ng ofi the spinning motor', v.the:heating elements, and the timer. Because of the inertia of;- the 4turning armature of the motor 2li, the's'pindle'Z l', and the elements secured thereto, the records 22 continue to spin for a considerablelength ottime' after the motor circuit Ellis broken. Thus, the record-s 22 continue to spin as 'theyy yare..exposed to the open air, which speeds the cooling'` thereof. Meanwhile centrifugal force `maintains the records 22 in planar configuration and keeps them from warping while they cool. When spinning ceases, the spindle 2i is' 'turned up (Figure 3),

and the records 22 are. removed. They maynowbe used again as blanks, and beA recorded upon.

Figures 14 through 23' illustrate a fully automatic embodiment of apparatus within the purview of the present invention. It is only necessary to load this apparatus with one` or-'more records and pressa button, inord'erto erase said records.

ln Figure 14, the .heating chamber 36- is shown in thecourse ci enclosingthe spinning records 22. A sin. the. case ,of the embodiment shown in Figures l-13, the heating chamber .36 ismounted upon a carriage 1.3 movable alongl a trackvv or channel "it, the. rollers 1.5 being. guidedl byftheguide rails 1e and 1.1. In addition,".a pulley. 18 is rotatably -j secured to the frame 2-1.fby.jour'naling means (not shown), and extends, a vshort distance: above the opening.19 -in the channel 14. Aca-ble S0 passes aroundl the. pulley 18, one. end ofA thel cable 8e3 being attached tothe :carriage 1:3,while the other. end is coiled clockwise aroundthe drurri B I. (Figure le). A corresponding pulley. 82 extends above the opening 83V disposedat the .other end of the channel 1li.' A second cable. 8.4. passes over the pulley 8,2l and connects the'` carriage V1.3y and the ,l drum 8l, the, vcable 84 beingi wound counterclockwise around the latter.

A pair of stops 85, 85. (bestshown. in Eigure. 15) limits the'travel of thejcarriage'ia along theehan-V nel 14'. Similarly, thestops 8 5, 86;-, define the end position ofv thecarriage .13,as it-jmoves inthe oppo site direction along the. channetlt after the. reo orde 2h52, have been reprocessed.. A- sthecarriage i3 approaches iis estreme 'weine to. the lef-i (Figure, 15). it. trips. en@ Opens the Suiten Si forming a partA of the controlI circuitdescribed below. AA similar switch' 83` "is, opened by the carriage '13 'as it appnnaches: the engi` of its trayel tothe right. Y

The drum 8l is4 turned. byy the server-,motor 911, through the shaft 89'. Asn shown byn directional arrows in Figure 14, clockwise rotation of the motor Elli causes the cable Smil townd upon: thef ditemi* ansihecablfl-ib unwieaibereby mevins the. Carriage liiethe.. left. 'lmove Seid carriage 13 to the right. the pirityiof" the' field 90b (Figure 17) of the motor 90 is reversed with respect to that of the armature 90a. Thus the motor 90 serves to move the heating chamber 36 in both directions along the channel l0. To clarify the manner in which the motor 90 is connected to a source of electric current to provide for rotation in either direction, the motor circuit is shown in duplicate in Figure 17, the circuit designated 9 Ia providing for clockwise rotation of the drum 8|, and the circuit designated 9| b providing for counterclockwise rotation of said drum 8|. When bridging members 92 and 93 close circuit 9|.a, current may be considered as flowing from the contact 94 to the contact 95. On the other hand, when the bridging members 96 and 91 of the circuit 9Ib close said circuit, the current through the armature is reversed, since the current flows from contact 95 to contact 94.

The members 92, 93, 96 and 91 are actuated automatically, and in the proper sequence to correctly move and position the heating chamber 36. This may be accomplished, for example, by the timing subassembly shown in Figures 18 and 19. Said subassembly includes an electric timer 98, of the type which turns the timer shaft |03 through precisely one complete revolution each time the switch 'I2 is actuated. The cams 99, |00, |I, and |02, are each keyed to the timer shaft |03, and rotate with it. Said cams are shaped to impose the desired program control upon the electrical circuits, and act through suitable cam follower mechanism. Thus, as the cam 99 turns, the rise and fall of the roller |04 moves the follower to close and open switch |06 in circuit |97, thereby controlling the record-spinning mo- :'z

tor 20. Said follower |05 pivots aboutI the line shaft |08, while the roller |04 is kept in contact with the cam surface by'means of the spring |09.

Cam |02 operates similarly through roller IIO and follower III to close or open, respectively, switch |I2 in circuit I I3-spring ||4 maintaining said roller ||0 in contact with the cam surface of cam |02. Thus cam |02 energizes and deenergizes heater coils 42 according to a pre-arranged pattern. In like fashion, the rollers II5 A and IIS transmit motion from the cams IOI and |02 to the followers ||1 and ||8 respectively. Said followers I|`| and I|8 each turn about the line shaft I 08, and are acted upon by springs I I9 and |20, respectively. Movement of the follower II controls the movement of the bridging members 92 and 93, and hence the leftward movement of the heater carriage '13; while follower I I 8 controls the position of the bridging members 91 and 98, and hence the movement to the right of said carriage 13.

In Figure 19, the rollers |04, |I0, ||5 and II6 are all shown in contact with a dwell portion of their respective cam surfaces. This is the condition which exists when the heating chamber 36 is in the position shown in Figure 1. This initial dwell, or null position is designated in Figures through 23 by the zero degree (0) markings adjacent the cams. Because of the different position of the follower the zero mark of cam |00 of Figure 21 is displaced counter-clockwise of the zero marks of the cams 99, IOI, and I02. As long as the rollers |04, I|0, I|5 and ||6 contact dwell portions of the cams, the interconnected switches of circuits |01, I|3, 9| a and 9|b, respectively, remain open, as shown in Figure 17. Conversely, as the rollers |04, |I0, IIS and IIB contact rise portions of their respective cams. the corresponding switchesare closed, and the corresponding components of the control system are energized.

As the timer 98 commences to turn. the rollers |04, I|5, and I|0 engage rise portions of the cams 99, |00, and |02 respectively, thereby causing the motor 20 to centrifuge the records 22, the heating elements 42 to heat the chamber 36, and the servo-motor (Figures 14 and 16) to move the chamber 36 to surround the records 22.

To safeguard against jamming the heating chamber 30 against the stops 85, 85 while the servo-motor 90 is running, the switch 81 is incorporated into circuit 9|a and is automatically opened by contact with the carriage 'I3 as the latter approaches its end position to the left. The heating chamber 36 then glides to a stop against the stops 85, 85. Shortly thereafter. the dwell portion of the cam |00 is reached by its roller I|5, which causes the bridging members 92 and 93 automatically to be lifted away from their engaging contacts.

After the heating of the records 22 has continued through about of cam travel, the dwell portion of the cam |02 is again reached. This opens switch I I2 and disconnects the heating elements 42 from the line 55. At about the same time, the rise portion of the cam |0I is reached by the roller IIS, which acts to close circuit 9| b of Figure 17. Since this reverses the armature connections relative to the field connections, hence the motor 90 commences to turn counterclockwise, and moves the heating chamber 36 to the right (Figure 14), away from the spinning records. Again, to safeguard against jamming the carriage 13 against the stops 86, 86 while the motor 90 continues to turn, I provide a switch 88 in the circuit 9|b which is opened upon contact with the carriage, thereby insuring that the motor 90 is disconnected from the line 55 just before the carriage 13 reaches the stops 86, 86.

After the heating chamber 36 has moved away from the records 22, the motor 20 continues to spin the records 20 until the dwell period of the cam 99 is reached. Using the cam proportions of Figures 20 through 23 for example, the motor 20 remains energized for about 140 of cam travel after the heating chamber has returned to its null position. Thus the records are power centrifuged while they cool in the air, which prevents them from warping while being cooled. When cam 99 presents its dwell surface to roller |04, switch I 06 is opened, thereby turning 01T the record-spinning motor 20. Timer 98 then completes its rotation of timer shaft |03 through 360, and comes to rest. The apparatus has then completed its cycle of operation, and is in its initial off" position, ready to repeat the cycle when button 'I2 is pressed again. The operator merely removes the resurfaced records, and reloads the apparatus with other records requiring erasure.

A record thus resurfaced has its sound track sensibly obliterated, so that even when the phonograph is set at maximum amplification, no message can be heard from the resurfaced record. At normal amplification, nothing is heard other than background scratch like that produced by a new blank record. The reconditioned record looks like a new blank record, although sometimes a faint trace of the original groove may be visually discerned even though it cannot be heard on the phonograph. This trace does not interfere with the fidelity of the sound recording subsequently placed upon the record. Advantageously, by means of my novel process a disk type thermo- 9 plastic blank may' be ii'sed o'v'r and over again, heine 'recorded upon, .transcribed; erased. and again recorded upon, through many cycles o'f such use. Y

It is obvious that the methods' taught herein may be used to resurface articles other than used phonograph records, and that the apparatus disclosed herein likewise may be adapted to resurface a variety .of thermoplastic articles."

I therefore claim as my invention:

1. Apparatus for erasing an embossed sound track from a used thermoplastic record disk having a center opening therein, comprising: a shaft spaced to engage said opening to support said disk by its central unised portion in a. plane at right angles to the shaft, a motor for rotating said shaft at a speed sufficient to maintain the disk flat while it is in a heated condition, a chamber normally spaced from said shaft, means for moving said chamber to substantially surround said disk when rotating on said shaft, catch means for retaining said chamber in position surrounding said disk, heater elements in said chamber, means for energizing said motor and said heater elements while said chamber surrounds said disk, timer means for releasing said catch means after a predetermined time interval, means for separating said chamber from said disk when said catch means is released, and

means for maintaining rotation of said shaft and the disk thereon after said chamber is separated therefrom until said disk is cooled.

2. A machine for reconditioning a used phonograph record disk of thermoplastic material to obliterate embossed record grooves therefrom, comprising rotatable means for holding a record disk by its central unused portion for rotation about its geometric axis; means for heating said record disk to a temperature suiicient to oblitera'te said grooves therefrom; power-actuated means for rotating said holding means and the disk thereon to maintain the disk flat by centrifugal action while it is in a heated condition; means for concurrently shutting off the actuating power to said rotating means and said heating means; and inertia means associated with said rotating means for maintaining rotation of said holding means after the power to said rotating means is shut off for an interval sufficient to maintain said record disk flat by centrifugal force until the disk has cooled.

3. A machine for reconditioning a used phonograph record disk of thermoplastic material to obliterate embossed record grooves therefrom, comprising rotatable means for holding a record disk by its central unused portion for rotation about its geometric axis; a heater for said record disk; a carriage for said heater mounted for moving the heater into an effective position in juxtaposition with said record disk and into an ineffective position away therefrom; means for rota-ting said holding means at a speed sufficient to maintain the disk flat by centrifugal force while the disk is in a heated condition; motor-driven means for moving said carriage; and switch means in said motor circuit operated by said carriage as said heater nears said effective and ineffective positions respectively for opening the motor circuit.

e. A machine for reconditioning a used phonograph record disk of thermoplastic material, to obliterate embossed recordations therefrom, comprising a rotatably-mounted shaft having means thereon for supporting a record disk by its central unused portion in a vertical plane for rotation vabout its 'geometrie axis, a heating means mounted for movement 'into an effective posi-tion wherein it -is juxtaposed to said record disk and into an ineffective position away 'from said disk, a vrnotor for driving said shaft and the disk thereon to maintain the disk `fiat by centrifugal action while it is in 'cheated condition, and pivoted mounting 'means for said shaft operable when said heating means is in ineffective posi-tion to move said shaft into a vertical position.

5. A machine for reconditioning used phonograph record disks of thermoplastic material, to obliterate embossed recordations therefrom, comprising a rotatably-.mounted horizontal shaft having clamping means and intervening record separators for holding a plurality of record disks by their unused central portions in axial alignment with said shaft and at space intervals along said shaft for rotation about their geometric axes in vertical planes; a heating chamber for embracing said plurality of mounted disks; a motor for rotating said shaft at a. speed to maintain said disks at by centrifugal action while the disks are in a heated condition, and a pivoted mounting for said shaft operable to swing the shaft into a vertical position to allow the record disks and said separators to be stacked on said shaft and held gravitationally in place until they are secured to the shaft by said clamping means.

6. A machine for reconditioning a used thermoplastic disk to obliterate embossed record grooves therefrom, comprising rotatable means for holding a record disk by its central unused portion for rotation about its geometric axis; a heating chamber mounted for movement into effective position wherein the chamber surrounds the disk mounted on said holding means and for movement into an ineffective position away from said disk; drive means for rotating said disk-holding means and for moving said heating chamber between effective and ineffective positions; means for disabling said drive means as to said heating chamber when the heating chamber reaches effective position; and a timing mechanism effective upon expiration of a predetermined interval during which said heating chamber is at rest in effective position for abling said drive means to return said heating chamber to ineffective position.

7. A machine for reconditioning a used thermoplastic disk to obliterate embossed record grooves therefrom, comprising rotatable means for holding a record disk by its central unused portion for rotation about its geometric axis; a heating chamber mounted for movement into effective position wherein the chamber surrounds the disk mounted on said holding means and for movement into an ineffective position away from said disk; means for rotating said diskholding means; means for moving said heating chamber from ineffective to effective positions and back again; means operable to start said rotating and moving means; and a unitary timing mechanism rendered operative by said starting means concurrently as said rotating and moving means are put in operation and including means controlling both said rotating and moving means to cause, in the sequence here named, said moving means to be disabled for a predetermined interval when said heating chamber reaches effective position, said moving means to be stopped when said heating chamber reaches ineffective position, and said rotating means to be stopped on expiration of a predetermined eiectiv position.

2,583,297 l 1 12 interval after said heating chamber reaches in- REFERENCES CITED 'Ihe following references are of record in the le of this patent:

UNITED STATES PATENTS 8. The combination set forth in claim 7 including an on-oi heater switch for the heating circuit of said heating chamber, means for closing said heater switch by said starting means as Number Name Date the latter is moved to starting position, and 2,265,032 Feyrer Dec. 2, 1941 means controlled by said timing mechanism to 2,340,131 Van Deventer Jan, 25, 1944 open said heater switch at the start of return 2,539,717 Banner Jan. 30, 1951 of said heating chamber to ineffective position. 10

ALBERT I. KEGAN. 

